Best Buy is introducing another special deal this weekend, offering a minimum of $150 for trade-ins of working iPhone 4s and iPhone 5 smartphones. Customers must buy a new smartphone with two-year contract on AT&T, Sprint or Verizon, however. The offer is good through the end of the day tomorrow, March 1. The chain has also reduced the price of the base 16GB iPhone 5s to $150 to match the buyback. With a number of carriers moving away from two-year contracts for its customers -- instead focusing on non-subsidized, but cheaper, monthly plans -- it may be affecting the bottom line of retailers like Best Buy because plans like AT&T Next do not, in many cases, require customers to pay money up front. For upgrade-eligible iPhone-owners looking to move
